Abstract Detail

Systematics Section/ASPT

Gahagen, Benjamin [1], Tomaz, Eduardo [2], Ballard, Harvey [3].

Investigation and cladistic analysis of morphological characters in Tovomita (Clusiaceae).

Tovomita Aubl. (Clusiaceae) is a relatively small genus (approximately 45 species) of trees, shrubs, and hemi-epiphytes ranging from Central America to central South America. Although the genus has definitive generic characteristics to justify segregation of species subsequent authors and collectors have nevertheless placed many species in Dystovomita (Engl.) D’Arcy, Chrysochlamys Poepp., and Clusia L. Past and present floras still include probable species of Tovomita that cannot be recognized with certainty or assigned to a genus due to the poor knowledge available. In addition to using macromorphology to circumscribe species in this genus, micromorphology and anatomical features are potentially taxonomically informative but have largely been neglected. While petiole vasculature and leaf epidermal features have been studied in related genera, and have been successfully used to differentiate species, little is known on the anatomy and micromorphology of Tovomita.  The aim of this study was to investigate the differences in Tovomita petiole anatomy and leaf micromorphology as well as assess the potential of using these characters along with macromorphology in a cladistic analysis.  Petiole cross sections were prepared by infiltrating and embedding the sample in wax and then sectioning with a microtome. Leaf epidermal peels were prepared by soaking the leaf samples in a solution of ethanol and hydrogen peroxide and then peeling apart the abaxial and adaxial surfaces for observation. Preliminary research has shown that individual species and species groups exhibit a combination of different stomatal types, subsidiary cell types, and differences in petiole vasculature that make them unique. Observations comprise stomatal size and density, type (whether paracytic or brachyparacytic), subsidiary cell margin (lobed or entire), and differences in the arc-shaped leaf trace including but not limited to the presence or absence of a medullary bundle. In addition, canals and mineral deposits are evident in leaf epidermal peels of certain species. These anatomical and micromorphological differences will aid in species circumscription as well as elucidate the evolutionary relationships within Tovomita in a cladistic analysis.

1 - Ohio University, 317 Porter Hall, Athens, OH, 45701, USA
2 - Ohio University, Environmental and Plant Biology, 317 Porter Hall, Athens, OH, 45701, USA
3 - Ohio University, ENVIR & PLANT BIOLOGY-PORTER H, 315 Porter Hall, Athens, OH, 45701-2979, USA

Keywords:
Tovomita
Clusiaceae
cladistics
Morphology
anatomy.

Presentation Type: Oral Paper:Papers for Sections
Session: 18
Location: Salmon/Boise Centre
Date: Tuesday, July 29th, 2014
Time: 9:30 AM
Number: 18007
Abstract ID:358
Candidate for Awards:None